Apparatus for controlling discharge lamps



Oct. 9, 1934. w. F. WESTENDORP 1,976,645

APPARATUS FOR CONTROLLING DISCHARGE LAMPs Filed June 7, 1933 2 Sheets-Sheet 1 PHASE CONTROLLER PHASE CONTROLLER Inventor: Wil Iem FTWestendorP,

His 'Attovhey.

Oct. 9, 1934. w. F. WESTENDORP APPARATUS FOR CONTROLLING DISCHARGE LAMPS Filed June 7. 1933 2 Sheets-Sheet Fig.5.

O n. :d r r U om .mSEA e .5 vW H TmE Patented Oct. 9, 1934 UNITED STATES PATENT OFFICE APPARATUS FOR CONTROLLING DIS- CHARGE LAMPS ration of New York Application June 7, 1933, Serial No. 674,697

12 Claims. .(Ol.176124) My invention relates to apparatus for controlling electric discharge lamps, and particularly to, the starting of such lamps and the regulation of the light thereof. It is well known to those skilled in the art that electric discharge lamps which are in the form of long, narrow tubes, sometimes termed positive column lamps, require some special means to cause them to start operating in addition to being connected with the source of current supply for the voltage at which they will operate after being started is not of itself sufiiciently high to cause them to start. Where such lamps are operated by alternating current they must be restarted once each 15 cycle if they are constructed to operate on onehalf cycle only of the alternating current, or twice each cycle if they are constructed to operate on both half cycles thereof.

It is one object of my invention to provide an 0 improved form of apparatus for applying a starting voltage to electric discharge lamps of this form which is simple in construction, which does not depend upon cooperating moving parts, and which is inexpensive to manufacture. Another object of my invention is to provide improved apparatus whereby the quantity of light produced by such discharge'lamps may be regulated at will in a convenient manner and without objectionable losses in the apparatus.

My invention will be better understood from the following description taken in connectionwith the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring to the drawings, Fig. 1 is a circuit 85 diagram illustrating one embodiment of '-my invention for starting nd controlling a single lamp operating on one half cle of an alternating current; Fig. 2, shows a detail of the discharge lamp of Fig. 1; Fig. 3 is a circuit diagram showing a 40 modification adapted for starting and controlling a number of lamps supplied from the same circuit; Fig. 4 illustrates a modified form for starting and controlling lamps constructed to operate on both half cycles of an alternating current and Fig. 5 shows a further modification wherein the lamps are provided with two cathodes and are adapted to operate on both half cycles of the alternating current supplied.

In Fig. 1 .of the drawings I have shown the electric discharge lamp 1 01! the elongated or positive column type comprising a tubular envelope of transparent material, such as glass'or quartz, having a cathode 2 in an enlargement or bulb at one .end and an anode 3 'at the opposite end. The cathode 2 may be either a not or a cold cathode, but preferably is a hot cathode, and in Fig. 2 is shown provided with a heater 5 of well known form, the source of heating current not being shown. If a cold cathode is used it may be of the well known mercury pool type. Depending upon the character of the light desired ,from the lamp the envelope after having been evacuated is supplied with mercury vapor under low pressure or with an inert gas, such as neon, sodium, krypton, etc. Inasmuch as a lamp of this 65 character has a negative volt-ampere characteristic a suitable impedance must be used in circuit with the lamp to hold the current within safe For this purpose I have shown the reactor 6 interposed in the connections between the lamp and the supply circuit 4 which, for example, may I be a 60 cycle 110 volt single phase alternating current circuit. The reactor 6 has in addition to the usual winding thereof the auxiliary winding 7 comprising a few turns of wire wound on the same core as the main windingand thereby comprising in effect a transformer whose purpose will be explained later.

As mentioned above, the discharge lamp 1 will not start naturally when connected with the source of current supply 4 but if it is started in each positive half cycle of supplied current, namely the half cycle in which its anode is positive with respect to its cathode, it will continue to operate through the remainder of each of those half cycles. In order to start the lamp in each positive half cycle I cause a voltage impulse to be applied to the lamp in each positive half cycle which impulse added to the voltage of the supply circuit is sufllcient to start a (115- charge in the lamp. The means which I have de-- vised for applying the voltage impulse for starting the lamp comprises the capacitor 9 arranged in series with the winding '7 and connected with the opposite sides of the supply circuit, a suitable control resistor 10 being included in this connection. The capacitor thus is charged from the supply circuit. To allow it to discharge quickly and at the proper instant through winding '1, I have provided the vapor electric discharge device or valve 12 having the control grid 13. The gridcathode circuit of the device 12 may be connected with any suitable control means for causing the. device to begin conducting current at a desired point on eachpositive half voltage wave.

In orderthat I may not only start the lamp, thus causing the lamp to start on each positive half cycle, but also may vary the amount of 11- lamination which the lamp shall give, I employ a 110 cycle of the applied phase control device as the control means. Such 42 in the Alexanderson Patent No. 1,655,037, January 3, 1928. By adjusting the position of the handle 15 of the device the phase of the voltage wave applied to the grid-cathode circuit of the vapor device may be advanced or retarded with respect to the voltage wave of the source 4, and that point on the latter voltage wave at which the capacitor discharges and the lamp starts may be varied accordingly. Since by the adjustment of handle 15 the lamp can be started at various points on each positive half cycle, it being understood that it always goes out at the end of each positive half cycle, that fraction of each positive half cycle through which the lamp is illuminated thus may be varied at will. Due to the persistence of vision the lamp appears to glow steadily but with' a brightness which depends upon that fraction of each positive half cycle through which it is illuminated.

The operation of the above described apparatus is as follows: During each positive half cycle of applied voltage, namely, the half cycle during which lamp 1 will operate, the capacitor 9 receives a charge from the source of supply. At that particular point in this half cycle at which the phase control apparatus 14 is set to trip the vapor device 12, thereby causing it to become conducting, the capacitor is allowed to discharge suddenly through the auxiliary winding 7 and the device 12, the latter device again becoming nonconducting at the end of the half cycle. Because of the high ratio of transformation between the. reactor winding and the auxiliary winding a relatively large voltage impulse is induced in the reactor winding. The resulting voltage applied to the lamp is suflicient to start a discharge between its cathode and anode and the lamp continues to operate for the remainder of that half cycle or until the current of that half cycle reaches zero. In a similar manner the lamp is started during each succeeding positive half cycle. By adjusting the position of the handle of the phase control device the instant of starting of the lamp during each positive half cycle of the supply voltage may be varied at will; a movement of the handle in one direction will came the vapor device to become conducting, and'hence the lamp to become illuminated somewhat earlier in each positive half cycle, and conversely a movement of the handle in the opposite direction will cause the vapor device to become conducting, and hence the lamp to become illuminated somewhat later in each positive halt cycle. Inasmuch as the interval of illumination of the lamp during each positive half cycle thus is varied the total light produced by the lamp is varied.

In Fig. 3 I have shown an arrangement for the control of a plurality of discharge lamps from a single control apparatus. Each lamp- 1 is connected with the supply circuit 4 in series with a separate reactor 6, each reactor being provided with an auxiliary winding 7 as in Fig. 1. While the several auxiliary windings 7 may, if desired, be connected with the capacitor 9 in parallel I prefer to connect these windings in series as illustrated in Fig. 3 for the reason that by so doing the starting of one lamp increases the available impulse for the others which obviously would not plurality of anodes 22, 23 whereby the lamps are adapted to operate on both the positive and the negative half cycles of the alternating current supply. Each lamp has two reactors 24 and 25 connected respectively in series with the anodes 22 and 23 thereof and each reactor has an auxiliary winding 26, the construction being similar to that shown in Fig. 1. In this case operating current for the several lamps is supplied through the vapor electric discharge devices 29 and 30 which, as shown, are arranged in series between the reactors of the lamps and opposite ends of the secondary of the supply transformer 31, the cathodes of all the lamps being connected with the midpoint of thesecondary. The phase con- -trol device 14 supplies the control impulses to the grid circuits of vapor devices 29 and 30 through the transformer 33. The capacitors 34 and 35 are similar to capacitor 9 of Fig. 1, and are connected as shown, in series with the auxiliary windings 26 of each group of reactors under the control of vapor devices 29 and 30. The operation of this form of my invention is similar to that of the form shown in Fig. 1 with the exception that each tube operates on both half cycles of the applied voltage, the two anodes of each tube being supplied with current alternately during each cycle and the point on each positive and negative half wave of applied voltage at which the lamp starts being controlled by the position of thephase adjusting device.

In Fig. 5 I have'shown a plurality of full wave discharge lamps 37 of a different type, namely, those having a hot cathode 38 at each end of the lamp. As in the form shown in Fig. 3 a single connect respectively with the two secondary windings 44 and 45 of the transformer 46 whose primary connects with the phase control device 14. In the operation of this modification one vapor device 40 allows the capacitor to discharge through the auxiliary windings at the proper instant on one half cycle, and the other vapor device 41 in a similar manner allows the capacitor to discharge through the auxiliary windings at the proper instant on the other half cycle. As in the preceding form the phase, control device provides for two starting impulses during each cycle and the lamps 37 which operate on both half cycles are regulated as to their brillianoy by the manipulation of the phase control apparatusin the manner already described.

.I have chosen the particular embodiments described above as illustrative of my invention, and it will be apparent that various other modifications may be made without departing from the spirit and scope of my invention which modifiprising flux producing means inductively related to said impedance and arranged to induce a startmg voltage therein. 1

4. In combination, a source of current'supply,

a discharge lamp connected therewith, an impedance arranged to limit the current taken by said lamp, a capacitor having a discharge current circuit and means for causing the discharge current of said capacitor to induce a voltage in said impedance for starting said lamp.

5. In combination, a source of alternating current supply, a discharge lamp connected therewith, an impedance in series with said lamp, means for inducing a starting voltage in said impedance, and means for selecting the point on the positive wave of said supply at which said voltage occurs.

6. In combination, a source of alternating current supply, a discharge lamp connected therewith, a reactor in series with said lamp, a capacitor having a discharge current circuit, means responsive to the discharge of said capacitor for inducing a voltage in said reactor for starting the lamp and means for varying the point on the alternating current-wave at which the discharge occurs.

7. In combination, a source of alternating current supply, a discharge lamp connected therewith, a reactor in series with said lamp, a capacitor connected to be charged from said supply, means for discharging the capacitor at various points on the alternating current wave and means for causing the discharge current to induce a voltage in said reactor.

8. In combination, a source of alternating current supply, a discharge lamp connected therewith, a reactor provided with an auxiliary winding and arranged in series with said lamp, a capacitor arranged to discharge through said winding, and means for controlling the point of the alternating current wave at which said discharge occurs.

9. In combination, a source of alternating current supply, a discharge lamp connected therewith, a reactor provided with an auxiliary winding and arranged in series with said lamp, a capacitor connected to be charged from said source and arranged to discharge through said winding and a grid controlled electron discharge device for controlling the discharge of said capacitor.

10. In combination, asource of alternating current supply, a discharge lamp connected therewith, a reactor provided with an auxiliary winding and arranged in series with said lamp, a capacitor connected to be charged from said source and arranged to discharge through said winding, a grid controlled vapor electric discharge device arranged to control the discharge of said capacitor and a, phase control device connected with the grid of said discharge device.

11. In combination, a source of alternating current supply, a plurality of discharge lamps connected therewith each having a reactive winding in circuit therewith provided with an auxiliary winding, a capacitor, a discharge circuit therefor including said auxiliary windings arranged in series and means for controlling the'discharge of said capacitor.

12. In combination, a source of alternating current supply, a plurality of discharge lamps connected therewith each having a reactor in series therewith provided with an auxiliary winding, a \capacitor arranged to be charged from said source, a discharge circuit for said capacitor. including said auxiliary windings connected in series and a phase controlled vapor electric discharge device in said circuit.

WILLEM F. WESTENDORP. 

